GNET Derived Mass Balance and Glacial Isostatic Adjustment Constraints for Greenland

Monitoring the Greenland mass balance (GMB) is crucial in the context of global sea level rise. Currently, three main methods are used to measure GMB, with the primary source of uncertainty arising from the glacial isostatic adjustment (GIA) contribution. Here, we propose a novel approach based on a simple methodology that uses the entire Greenland GNSS network (GNET) as an instrument to monitor the present-day mass changes. Our method is validated against GRACE-derived GMB, and we find a very good agreement. This leads to an independent methodology for estimating present-day mass changes from GNSS, bridging the gap between GRACE and GRACE-FO in GMB estimates. Through a combined analysis of GMB from GRACE and GNET, we identify a consistency relation between the gravity and uplift signature of GIA, providing a new robust constraint for GIA models.